I. Field of the Invention
This invention relates generally to high speed metal punching equipment suited for installation in a turret-style punch press and more particularly to the design of a punch assembly used in such equipment that allows for quick removal of a worn punch insert from the punch guide for refurbishment and return or replacement.
II. Discussion of the Prior Art
To provide increased mean-time-to-repair of punch assemblies used in high-speed CNC controlled turret punch presses, it has proved expedient to employ a high-grade high speed steel insert such as American National Standards Institute M2 steel punch point insert affixed to the end of a lower cost steel punch driver to reduce cost of the punch press assembly. Notwithstanding the use of such a high-grade and relatively expensive punch point insert, after a period of use in punching holes through sheet steel and other metals, it becomes necessary to replace the punch point insert with a new or resharpened one. To reduce the downtime of the turret punch press for such punch point insert replacement, it is desirable that an operator be able to perform this task in a minimum amount of time and most preferably without the need for special hand tools.
In prior art punch assemblies having a two-piece driver/insert combination, it has generally been necessary to first remove the punch driver and insert from the upper end of the punch guide and subsequently remove the punch insert from the punch driver so that the punch point insert can be replaced with a new or refurbished unit. The present invention makes possible reduced manufacturing costs, such as machining expenses e.g. through the use of stamped components while at the same time simplifying punch point replacement by providing a way to releasably clamp the stripper member to the end of the punch guide and the punch point insert to the punch driver. The clamping mechanism employed is most preferably actuated by hand and in most cases without the need for any special tools or without the need to remove the punch driver and insert from the punch guide.